Digital printing and finishing method for fabrics and the like

ABSTRACT

A method of digital printing and finishing for fabrics is provided. The method includes a step of unwinding a fabric from a first reel. A step of compensating the speeds and of spreading the fabric for its positioning on a conveyor belt provided with supporting elements on which a digital printing step occurs is provided. A step of drying the fabric is provided. A step of winding the fabric onto a second reel is provided. These steps are being executed at corresponding stations arranged in sequence with respect to each other and the fabric passing through them continuously, transversely to the conveyor belt, there being a plurality of bars provided with printing heads which are controlled electronically and synchronized with the movement of the conveyor belt.

TECHNICAL FIELD

The present invention relates to a digital printing and finishing method for fabrics and the like.

BACKGROUND ART

The conventional method of digital printing and finishing for fabrics, starting with a fabric for conventional printing that has previously been rendered hydrophilic in order to allow the penetration of conventional printing pastes, is made up of a sequence of steps that are executed independently of each other.

More precisely, this sequence consists in a step of preparing the fabric for digital printing, in which the fabric for conventional printing is impregnated with adapted substances in order to enable the fixing of the color in order to subsequently be dried, a printing step, in which the fabric is printed and dried, a steaming step, in which the fabric is placed in a. steaming chamber for a period that can vary from ten to thirty minutes according to the type of fabric and to the type of printing ink used, a washing step, in which the fabric is washed to remove excess quantities of ink, and a drying step, in which the fabric is dried.

This conventional method suffers the drawback of displaying limited productivity because of the fact that the individual steps occur independently of each other.

In order to speed up the method of printing, a known technique is to have the washing and drying steps occur continuously. This attempt at speeding the method up is however not sufficient to adequately reduce the processing times. Disclosure of the invention

The aim of the present invention consists in providing a method of digital printing and finishing for fabrics that is faster than the conventional. method of digital printing and finishing, while increasing the productivity of the system.

Within this aim, an object of the present invention consists in providing a method of digital printing and finishing for fabrics that is simple and effective, while at the same time ensuring low costs of implementing the system and production costs that are economically advantageous when compared to those of the known art.

Another object of the present invention is to provide a method of digital printing and finishing for fabrics that limits manual intervention from the operator as far as possible.

Another object of the present invention is to provide a method of digital printing and finishing for fabrics that, thanks to its peculiar implementation characteristics, is capable of offering the widest guarantees of reliability and safety in use.

This aim and these and other objects which will become better apparent hereinafter, are achieved by a method for printing and finishing for fabrics and the like, characterized in that it comprises a step of unwinding a fabric from a first reel, a step of compensating the speeds and of spreading said fabric in order to position it on a conveyor belt provided with supporting means on which a digital printing step occurs, followed by a step of drying said fabric and a step of winding said fabric onto a second reel, said steps being performed in corresponding stations arranged in sequence with respect to each other and said fabric passing through said stations continuously, transversely to said. conveyor belt there being a plurality of bars provided with printing heads which are controlled electronically and synchronized with the movement of said conveyor belt.

BRIEF DESCRIPTION OF THE DRAWINGS

Further characteristics and advantages of the invention will become better apparent from the detailed description of two preferred, but not exclusive, embodiments of a method of printing and finishing for fabrics and the like, which are illustrated by way of non-limiting example in the accompanying drawings, wherein:

FIG. 1 is a schematic side elevation view of a system according to a first embodiment of a method of printing and finishing for fabrics and the like, according to the present invention;

FIG. 2 is an enlarged-scale detailed view of the station corresponding to the printing step of the system shown in FIG. 1;

FIG. 3 is a schematic plan view from above of the station shown in FIG. 2;

FIG. 4 is a schematic side elevation view of a system according to a second embodiment of a method of printing and finishing for fabrics and the like, according to the present invention.

WAYS OF CARRYING OUT THE INVENTION

With reference to the figures, the first embodiment of the method of printing and finishing for fabrics and the like, according to the invention, is performed by a system, generally designated in FIG. 1 by the reference numeral 1 a, and comprises a step of unwinding a fabric 2 from a first reel 3, a step of compensating the speeds and of spreading the fabric 2 in an adapted station 4 for positioning it on a conveyor belt 5 provided with supporting means, for example of the adhesive type, on which a. digital printing step occurs.

Advantageously, transversely to the conveyor belt 5, there is a plurality of bars 6 provided with printing heads 7 which are controlled electronically and synchronized with the movement of the conveyor belt 5. More precisely, the printing heads 7 are of the piezoelectric ink-jet type and are positioned on each one of the bars 6 in such a manner as to cover the width of the conveyor belt 5 and allow continuous printing.

Subsequently a step of drying the fabric 2 and a step of winding it onto a second reel 11 are provided. This drying step can occur with hot air in a steaming chamber 12 or the like.

Differently, in the second embodiment, for which the corresponding system 1 b is shown in FIG. 4, between the unwinding station and the printing station a step can be provided of immersion of the fabric 2 unwound from the first reel 3 in a tank 8 containing an aqueous solution 9 comprising at least one or more substances selected from the group constituted by pH stabilization. compounds and salts adapted to facilitate the fixing of the ink on the fabric 2 in the subsequent steaming step described below.

Conveniently, following the above mentioned immersion, a step is provided of pressing the fabric 2 impregnated with the aqueous solution 9 through a pair of presser rollers 10 in such a manner as to eliminate the excess part of the aqueous solution 9 from the fibers of the fabric 2.

Following the digital printing step, a step is provided of steaming the fabric 2 printed and impregnated with the aqueous solution 9 through a steaming chamber 12 in such a manner as to fix the ink to the fabric 2.

In this step, the fabric 2 retains a level of humidity similar to that of the previous steps and., given the speed at which this step occurs, which is comprised between 1 and 100 meters per minute, is such as to accelerate the process of penetration of the color into the fibers of the fabric 2.

Moreover, thanks to a steam temperature that is adapted to the process under conditions of atmospheric pressure, it is sufficient for the fabric 2 to remain in the steaming chamber 12 for 10 to 40 seconds in order to obtain the required fixing.

Conveniently, the steaming chamber 12 is dimensioned as a function of the top speed of the printing step, so as to ensure that the fabric 2 remains inside the steaming chamber 12 for a sufficient time.

Thereafter, a step can be provided of washing the printed and steamed fabric 2 which is adapted to eliminate from the fabric 2 the excess part of the ink by means of immersion in an adapted tank 13.

The fabric 2 is then dried and brought back to its initial size through two adapted machines 14 and 15 or it is simply dried and subsequently rewound onto the reel 11.

To sum up, in both of the proposed embodiments, the method according to the invention comprises a sequence of steps performed in corresponding stations arranged in sequence with respect to each other with the fabric 2 passing through all of them continuously.

More precisely, with regard to the first embodiment, the continuous method of digital printing and finishing, according to the invention, is adapted, for example, to fabrics printed with acid or disperse inks and, with regard to the second embodiment, the continuous method of digital printing and finishing, according to the invention, is adapted, for example, to fabrics printed with reactive inks such as monochloro/dichloro triazine and vinyl sulfone.

In practice it has been found that the method of digital printing and finishing for fabrics and the like, according to the present invention, achieves the intended aim and objects in that it is much faster than the conventional methods of digital printing.

Another advantage of the method, according to the present invention, consists in that it enables an energy saving as a result of the reduction of the number of drying processes and the reduction of the evaporation time.

A further advantage of the method, according to the present invention, consists in that, thanks to the continuity of the process, the movement is eliminated of the fabric between the several necessary steps to obtain the required product.

The method of printing and finishing for fabrics and the like thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the appended claims.

For example, instead of having the fabric on reels both in input and in output, it can be arranged. in sheets.

Moreover, all the details may be substituted by other, technically equivalent elements.

In practice the materials employed, provided they are compatible with the specific use, and the contingent dimensions and shapes, may be any according to requirements.

The disclosures in Italian Patent Application No. MI2010A002176 from which this application claims priority are incorporated herein by reference.

Where technical features mentioned in any claim are followed by reference signs, those reference signs have been included for the sole purpose of increasing the intelligibility of the claims and accordingly such reference signs do not have any limiting effect on the interpretation of each element identified by way of example by such reference signs. 

1-9. (canceled)
 10. A digital printing and finishing method for fabrics and the like, the method comprising: unwinding a fabric from a reel, compensating the speed of the fabric with the speed of a conveyor belt while spreading the fabric on the conveyor belt, digitally printing the fabric while the fabric continuously moves through a printing station on the conveyor belt, and then drying the printed fabric, wherein digitally printing the fabric comprises printing the fabric with electronically controlled printing heads synchronized with the movement of the conveyor belt and mounted on a plurality of bars extending across the conveyor belt, the printing heads being arranged on the bars in such a manner as to together cover the width of the conveyor belt and allow continuous printing of the fabric in a single pass.
 11. The method according to claim 10, wherein the positioned fabric is held to the conveyor belt with adhesive.
 12. The method according to claim 10, wherein the printing heads are piezoelectric ink-jet heads.
 13. The method according to claim 10, further comprising a step of immersing the fabric unwound from the first reel in a tank containing an aqueous solution before positioning the fabric on the conveyor belt.
 14. The method according to claim 13, wherein the aqueous solution comprises at least one or more substances selected from the group constituted by pH stabilization compounds and salts.
 15. The method according to claim 13, further comprising, after immersing the fabric in the tank and before positioning the fabric on the conveyor belt, pressing the fabric to remove excess aqueous solution from fibers of the fabric.
 16. The method according to claim 15, further comprising steaming the printed fabric in a steaming chamber to fix the ink to the fabric before drying the fabric.
 17. The method according to claim 16, further comprising washing the printed and steamed fabric before drying the fabric.
 18. The method according to claim 10, wherein the printing heads are arranged in a staggered pattern comprising multiple rows of printing heads.
 19. The method according to claim 20, wherein the printing heads comprise a first set of heads arranged in multiple rows and supported on a first bar extending across the conveyor belt, and a second set of heads arranged in multiple rows and supported on a second bar extending across the conveyor belt.
 20. The method according to claim 15, wherein the fabric is pressed to remove the excess aqueous solution immediately before printing.
 21. The method according to claim 15, wherein the fabric is pressed to remove the excess aqueous solution after being positioned on the conveyor belt.
 22. A fabric printing and finishing method, comprising: pretreating a length of fabric by immersing the fabric in a tank containing an aqueous solution, thereby impregnating the fabric with the aqueous solution; positioning the pretreated fabric on a continuously moving conveyor belt; with the fabric remaining on the continuously moving conveyor belt, printing the fabric in a printing station comprising multiple discrete printing heads of discrete width and mounted to span, in combination, a printing width wider than any of the discrete printing heads; and then drying the printed fabric.
 23. The method according to claim 22, wherein positioning the pretreated fabric on the conveyor belt comprising adhering the fabric to a surface of the belt.
 24. The method according to claim 22, wherein the printing heads are arranged in a staggered pattern comprising multiple rows of printing heads.
 25. The method according to claim 22, wherein the printing heads comprise a first set of heads arranged in multiple rows and supported on a first bar extending across the conveyor belt, and a second set of heads arranged in multiple rows and supported on a second bar extending across the conveyor belt.
 26. The method according to claim 22, further comprising, after immersing the fabric in the tank and before positioning the fabric on the conveyor belt, pressing the fabric to remove excess aqueous solution from fibers of the fabric.
 27. The method according to claim 26, further comprising steaming the printed fabric in a steaming chamber to fix the ink to the fabric before drying the fabric.
 28. The method according to claim 27, further comprising washing the printed and steamed fabric before drying the fabric.
 29. The method according to claim 26, wherein the fabric is pressed to remove the excess aqueous solution immediately before printing.
 30. The method according to claim 26, wherein the fabric is pressed to remove the excess aqueous solution after being positioned on the conveyor belt. 